The present invention relates to a temperature control device and method for an optical storage and retrieving apparatus, and especially a temperature control device and method using a temperature detecting apparatus to control the rate, the tracking loop gain, the velocity and braking slope of the data read/write device of the optical storage and retrieving apparatus for lowering the temperature of the optical storage and retrieving apparatus during operation.
With the substantial increasing of amount of data manipulated by state-of-art computer, the optical storage media such as CD-ROM or MO disk, has been a minimum requirement to a computer system. The optical storage and retrieving apparatuse such as a CD-ROM drive serve as an intermediate device retrieving data stored in the CD-ROM and transferring the data into a computer for further operation.
Referring to FIG. 1, a typical optical storage and retrieving apparatus 10 includes a carry device 11, a data read/write device 12, a guider 13, a servo control device 14, a driving device 15 and a CPU 16. The data read/write device 12 is supported by the guider 13 and receives an actuating signal from a servo control device 14 for commanding the pickup 12 move at a velocity and a braking slope on the guider 13. The carry device 11 carries an optical storage medium 17 and receives a driving signal sent by the driving device 15 to selectively rotate the optical storage medium 17. The servo control device 14 outputs a retrieving signal to the data read/write device 12 and the data read/write device 12 emits an incident light signal to the optical storage medium 17. The incident light signal is reflected by the optical storage medium 17 as a reflecting light signal. The reflecting light signal is received by the data read/write device 12 and then the data read/write device 12 outputs a corresponding voltage signal to the servo control device 14. The servo control device 14 then amplifies the voltage signal with a tracking loop gain to generate a tracking signal. Using the tracking signal, the servo control device 14 controls the incident light signal of the data read/write device 12 to closely track the data track on the optical storage medium 17. The CPU 16 is operatively connected to the servo control device 14 and the driving device 15 in order to command and control the servo control device 14 and the driving device 15 such that the contents recorded in the optical storage medium 17 are correctly and uninterruptedly retrieved.
However, in order to accommodate a large amount of multi-media data transfer required by a user, the optical storage and retrieving apparatus 10 has to retrieve the recorded contents in the optical storage medium 17 at a high speed. Therefore the earlier 2xc3x97 CD-ROM has lost its market and a 40xc3x97 or higher CD-ROM dominates in the market. A higher speed of CD-ROM implies a higher rotation rate of the carry device 11 and a higher velocity of the data read/write device 12 moving on the guider 13. Nevertheless, the carry device 11 and the data read/write device 12 tends to generate heat under high rate operation and further to elevate the internal temperature of the CD-ROM. Most notable of all, in order to match up with the fast operation of the carry device 11 and the data read/write device 12, the servo control device 14 and the driving device 15 also have to work at a higher frequency. ICs in the servo control device 14 and the driving device 15 therefore generates more heat due to high frequency operation and again results in the elevation of internal temperature of the optical storage and retrieving apparatus 10.
Other than the problem resulting from high- speed operation of the CD-ROM stated above, as the CD-ROM operates in an environment of higher temperature, the internal temperature of the CD-ROM rises with ambient temperature. All circumstances of the internal temperature being elevated often lead to an unstable operation condition of the CD-ROM while retrieving the contents of the optical storage medium 17. The unstable situations are directly and mainly due to the severe variation of working characteristics of many ICs in the servo control device 14. As the temperature is elevated to a certain degree, the operation characteristics of driving device 15 and the pickup of the data read/write device 12 vary substantially. Therefore, the focusing, tracking and seeking operations of the CD-ROM are unstable. The read/write ability of the CD-ROM is deteriorated. While the un-expected condition happens, one could only lower the control parameters, including the rate of the carry device 11, the value of the tracking loop gain, the velocity and the braking slope of the data read/write device 12, to recover the read/write ability of the CD-ROM.
To lower the temperature, the conventional approach is to improve the efficiency of heat dissipation by using heat dissipation fin having a larger surface or to improve the ventilation by increasing the number of ventilation holes or by re-arranging the relative position of each components in the CD-ROM. However, this type of approach can only solve the issue of heat generation due to high frequency operation of the ICs and can not effectively and totally solve the issue of heat generation resulting from CD-ROM""s operating in a high-temperature environment or operating at high speed.
The present invention provides a temperature control device situated within the optical storage and retrieving apparatus. When the internal temperature of the optical storage and retrieving apparatus reaches a predetermined value, the temperature control device causes the associated control parameters operating the optical storage and retrieving apparatus to be lower such that the optical storage and retrieving apparatus retrieves data accurately.
Another object of the present invention is to provide a temperature control method for an optical storage and retrieving apparatus. The method, based on the internal temperature value of the CD-ROM, is able to lower the rate of the carry device in the optical storage and retrieving apparatus, and/ or to lower the tracking loop gain of the servo control device, and/or to lower the velocity and braking slope of the data read/write device so as to command the optical storage and retrieving apparatus retrieve data accurately.
To further elaborate the way, the structure and the characteristics of the present invention, the following preferred embodiments are illustrated accompanied with the attached figures. While what are stated below are only preferred embodiments of the present invention, it is to be understood that the present invention is not limited by the preferred embodiments. The claims of the invention shall cover all equivalent or variations and modifications according to the spirit of the invention.